000
FXUS63 KAPX 071513
AFDAPX
Area Forecast Discussion
National Weather Service Gaylord MI
1013 AM EST Thu Dec 7 2017
.UPDATE...
Issued at 1013 AM EST Thu Dec 7 2017
Deep cyclonic flow...modest synoptic moisture and over-lake
instability continues to produce lake effect snow showers
impacting much of our CWA this morning. NW flow...multi-banded
structure continues to target the NW half of our CWA for the
greatest chance of snow showers as well as highest snow
accumulations. Locations between Mancelona...Kalkaska...Gaylord
and Alba have reported around 12 to 16 inches of new snow over the
past 24 hours...which appears to be the general location of max
lake snowfall for this event.
Low level winds will remain generally from the NW for the balance
of the day...which will continue to focus highest POPs and
greatest new snow amounts across the NW half of our CWA. Expect
another 1 to 3 inches of new snow by this evening for these areas.
Temps will only warm a few degrees...with high temps in the mid
20s to around 30 degrees.
&&
.NEAR TERM...(Today through Tonight)
Issued at 340 AM EST Thu Dec 7 2017
...Accumulating lake snows to continue...
High impact weather potential...lake effect snow, which will be
heaviest this morning and again late tonight.
Wnw-flow lake effect snow (LES) is in progress in northern lower MI,
with nw/nnw banding on Superior. A shortwave is dropping across the
region this morning, with an associated surface trof presently
pushing southward into upper MI. This surface trof is contributing
greatly to the wind shift between Superior and Lake MI. Another
shortwave will start to dive into northern Ontario tonight, with
further impacts on both winds and synoptic-scale moisture. LES
trends are the main concern.
Expect healthy LES into midday. Incoming surface trof will amp up
1000-850mb convergence, particularly in northern lower MI.
Inversion heights wobble up to around 7k ft, and the mid-levels
are quite moist, until abrupt drying arrives this afternoon.
In eastern upper MI, ongoing stronger bands in eastern upper MI are
poking into Curtis, Trout Lk, and Brimley. 1000-850mb winds progged
to be rather wobbly up that way this morning, so not sure that bands
will really settle in before substantial backing arrives this
afternoon. (At the moment, Superior bands are slowly translating
eastward.) Will kick morning snow amounts up to 2-3 inches in
western Chip. Per coord with MQT, will extend advisory up there thru
noon.
In northern lower MI, stronger returns have been focused from
Bellaire to Frederic. Signs of some very slow veering of the winds
within this band, drifting a touch southward. Southern Antrim and
northern Kalkaska should be the primary spot for snow this
morning (as it has looked over the past few runs now). Localized
4-inch accums should work for the daylight morning hours. Current
headlines appear fine, am keeping an eye on Crawford Co for a
potential upgrade.
This afternoon, 1000-850mb winds will abruptly back to the west,
ahead of the next incoming shortwave. Much drier mid-level air
briefly pushes in. Anticipate LES to continue, but in a disrupted
and weaker fashion. Accums will commonly be around an inch in the
snowbelts this PM, with LES eventually getting up to Ltl Trav Bay
in northern lower MI, and confined to Whitefish Bay in eastern
upper.
Max temps mid 20s to lower 30s.
Tonight, that incoming shortwave carves out a weak surface low just
ne of Superior. 1000-850mb winds will further back to the wsw in
response. Airmass remains somewhat dry in the mid-levels to start
the evening, but that goes away overnight, and inversion heights
bump back up to 8-9k ft. Anticipate snow amounts in the 3-4" range
tonight from Ltl Trav Bay to Cheboygan and across to Drummond Isl.
Expect this will be an advisory-level event, but will refrain from
dropping that on top of the ongoing headlines. Elsewhere, snow
accums will be an inch or less. Could be touch of blowing/drifting
in exposed locales late tonight, as the pressure gradient tightens
and winds get a bit gustier.
Min temps teens to around 20f.
&&
.SHORT TERM...(Friday through Saturday)
Issued at 340 AM EST Thu Dec 7 2017
...Uptick in the intensity of lake effect snow...
High Impact Weather Potential: Accumulating lake snow across
northwest lower and eastern upper Friday into Friday evening.
Accumulating snow across all areas overnight Friday into Saturday.
Primary Forecast Concerns/Challenges: Location and amounts of lake
effect snow remain the primary threats as well as potential impacts
through the period.
Moisture lingers from a departing short wave Friday leading to an
uptick in lake effect snow shower activity (inversion heights
increase to between 7000 and 8000 feet). Westerly flow slowly veers
into the west northwest Friday afternoon and evening. So expect
decent lake effect snow bands to add up to at least another few
inches in west/west northwest flow favored areas Friday into Friday
night. Headlines will likely be needed but we need to let the
current headlines go away first before issuing any new ones. An
Alberta Clipper then drops down into the region overnight Friday
into Saturday (likely tracking by just to our south). Winds should
initially become lighter out of the northeast late Friday night into
Saturday morning before increasing and turning into the north
Saturday afternoon. So expect snow to spread into all areas
overnight Friday into Saturday with some enhancement in
north/northeast areas likely. Accumulations should be on the order
of between a couple and a few inches (but enhancement could add more
to totals).
.LONG TERM...(Saturday night through Wednesday)
Issued at 340 AM EST Thu Dec 7 2017
...Cold with periods of snow and lake effect snow...
No real letup in the cold foreseen any time soon with the trough
remaining anchored across the region. In addition, disturbances
dropped down through the flow from the north and possibly a surface
low or two moving by to our south (extended models vary on the
details) will lead to shifting winds through the middle of next
week. So expect bouts of snow and lake effect snow to
continue (especially near Lake Michigan).
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 644 AM EST Thu Dec 7 2017
Lake effect snow showers continue with variable conditions.
Cold air crossing Lake MI continues to generate clouds and snow
showers for northern lower MI. The TAF sites near Lake MI will
continue to get the worst of it, especially TVC and MBL. Expect
variable conditions, but occasional IFR, especially this morning.
Lake effect will weaken as it shifts north this afternoon and
evening, but is likely to intensify overnight in the PLN area.
Ongoing w to nw winds will back to the sw tonight.
&&
.MARINE...
Issued at 340 AM EST Thu Dec 7 2017
W to nw winds will tend to decrease a bit further today, while
backing toward the w today and even sw tonight. However, those
winds will start to pick up again overnight, as weak low pressure
spins up just ne of Superior. May be a lull in many areas where
advisory-level conditions are not met, but it won`t be long enough
before winds/waves increase again late tonight and Friday. Have
gone ahead and extended small craft advisories on all waters into
Friday evening.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY until 4 PM EST this afternoon for MIZ020-
025-026-028-031>033.
WINTER STORM WARNING until 4 PM EST this afternoon for MIZ019-
021-022-027.
WINTER WEATHER ADVISORY until noon EST today for MIZ008.
LH...SMALL CRAFT ADVISORY until 11 PM EST Friday for LHZ345>349.
LM...SMALL CRAFT ADVISORY until 11 PM EST Friday for LMZ323-341-342-
344>346.
LS...SMALL CRAFT ADVISORY until 11 PM EST Friday for LSZ321-322.
&&
$$
UPDATE...MR
NEAR TERM...JZ
SHORT TERM...AS
LONG TERM...AS
AVIATION...JZ
MARINE...JZ